Listen to nearby robots in State-Machine

[tylerferrara]

Depends on #14 and #12

• Remove 'all-knowing' connected neighbors funciton
• Listen to coms topic for connected neighbors
• TEST

[tylerferrara]

For my own sanity, I made a visual representation of the coordination between physics simulator and network simulator.

Physics Sim | ARGoS or Gazebo

• Advances time and updates the environment accordingly
• Generates possible paths network packets could travel between agents

Network Sim | Language-agnostic program

• Determine which packets, between agents, should be dropped, modified, or passed through.

In order to synchronize these simulators, they are controlled by coordinating ROS nodes (coordinators) which both keep track of time. Essentially, they must use the same clock.

Physics Coordinator | ROS Node

• Pass path data to the Network Coordinator
• Advance & stop the Physics Sim

Network Coordinator | ROS Node

• Capture all network packets from agents
• Send captured packets, and path data to Network Sim
• Delay, drop, modify, or pass through packets in accordance to the Network Sim

Here's a visual example of how all these components work together:

[tylerferrara]

For interest of time, I'm looking to hack this flow to simply implement line-of-site for a simple demo.
Our goal is to ONLY hold packets for robots that don't see each other. In this way, I can ignore all channel data from the Physics Sim and simply listen to each robot's /robotX/line-of-site topic, found within the argos_bridge package. This is the quickest way to implement line-of-site communications between robots.

In the future, we can follow the intended design of ROS-Net-Sim found in the accompanying academic paper. This requires a global understanding of absolute position and orientation of each robot. From speaking with @AshayAswale, the Buzz language can help us with this if we decide to move away from the hacky line-of-site